1. Technical Field
The present invention relates to a system which performs printing.
2. Related Art
A printing device typically performs printing based on data (dot data) indicating presence/absence of dot formation for each pixel. The dot data is typically generated by converting image data in an RGB format. As the resolution of an image increases, the time required for the conversion increases.
Then, known is a technique of grouping a plurality of pixels and performing processing in accordance with presence/absence of an edge in each group so as to reduce the time required for conversion. The edge referred to herein indicates a borderline generated by sharp change of color or brightness. In this technique, the conversion is performed for a group including the edge in the existing manner, while information is compressed and the conversion is performed for a group including no edge. The conversion is typically executed by a host device (computer) which communicates with a printer. Dot data generated by the conversion is transferred from the host device to the printer as data for printing. The printer performs printing based on the transferred dot data (for example, JP-A-2004-289274).
In the above-mentioned existing technique, an object that both the reduction in the time required for transferring data for printing to the printer and the suppression of deterioration of print image quality are achieved at the same time has left unsolved. In particular, in recent years, a condition in which the time required for transferring data from the host device to the printer corresponds to a rate-controlling factor for print processing has been generated due to improvement of a conversion speed to dot data by the host device and improvement of a paper feeding speed by a line printer. Therefore, a data transfer time needs to be reduced. It is needless to say that the data transfer time can be reduced easily by lowering the resolution. However, image quality is deteriorated if the resolution is lowered. In this manner, there has been an object that both the reduction in the time required for transferring data to the printer and the suppression of deterioration of print image quality are achieved at the same time.